1114 lines
31 KiB
Markdown
1114 lines
31 KiB
Markdown
---
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title: QueryNode
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description: >
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QueryNode defines a source and a schedule for processing batch data. The data is queried from an InfluxDB database and then passed into the data pipeline.
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note: Auto generated by tickdoc
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menu:
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kapacitor_1_5_ref:
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name: QueryNode
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identifier: query_node
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weight: 220
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parent: nodes
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---
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The `query` node defines a source and a schedule for processing batch data. Data is queried from InfluxDB, computed by the `query` node, and then passed into the data pipeline.
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Example:
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```js
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batch
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|query('''
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SELECT mean("value")
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FROM "telegraf"."default".cpu_usage_idle
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WHERE "host" = 'serverA'
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''')
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.period(1m)
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.every(20s)
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.groupBy(time(10s), 'cpu')
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...
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```
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In the example above, InfluxDB is queried every 20 seconds; the window of time returned spans 1 minute and is grouped into 10 second buckets.
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To use InfluxQL advanced syntax for functions in the `query` node, you must express part of the InfluxQL query in the TICKScript. Advanced syntax computes the nested aggregation over time buckets, and then applies the outer aggregate on the results.
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For example, the following InfluxQL script, which calculates the non-negative difference of the 10-second mean of cpu usage for every cpu, isn't valid for the `query` node:
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```js
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SELECT non_negative_difference(mean("value"))
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FROM "telegraf"."default"."cpu_usage_idle"
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WHERE "host" = 'serverA'
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GROUP BY time(10s), "cpu"
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...
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```
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To calculate the result above for the `query` node, you must specify grouping and the outer aggregate using TICKScript:
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```js
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batch
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|query('''
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SELECT mean("value")
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FROM "telegraf"."default".cpu_usage_idle
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WHERE "host" = 'serverA'
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''')
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.period(1m)
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.every(1m)
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.groupBy(time(10s), 'cpu')
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| difference('max_usage')
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| where(lambda: "difference" >= 0)
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...
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```
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### Constructor
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| Chaining Method | Description |
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|:---------|:---------|
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| **query ( `q` `string`)** | The query to execute. Must not contain a time condition in the `WHERE` clause or contain a `GROUP BY` clause. The time conditions are added dynamically according to the period, offset and schedule. The `GROUP BY` clause is added dynamically according to the dimensions passed to the `groupBy` method. |
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### Property Methods
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| Setters | Description |
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|:---|:---|
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| **[align](#align) ( )** | Align start and stop times for queries with even boundaries of the QueryNode.Every property. Does not apply if using the QueryNode.Cron property. |
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| **[alignGroup](#aligngroup) ( )** | Align the group by time intervals with the start time of the query |
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| **[cluster](#cluster) ( `value` `string`)** | The name of a configured InfluxDB cluster. If empty the default cluster will be used. |
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| **[cron](#cron) ( `value` `string`)** | Define a schedule using a cron syntax. |
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| **[every](#every) ( `value` `time.Duration`)** | How often to query InfluxDB. |
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| **[fill](#fill) ( `value` `interface{}`)** | Fill the data. Options are: |
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| **[groupBy](#groupby) ( `d` `...interface{}`)** | Group the data by a set of dimensions. Can specify one time dimension. |
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| **[groupByMeasurement](#groupbymeasurement) ( )** | If set will include the measurement name in the group ID. Along with any other group by dimensions. |
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| **[offset](#offset) ( `value` `time.Duration`)** | How far back in time to query from the current time |
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| **[period](#period) ( `value` `time.Duration`)** | The period or length of time that will be queried from InfluxDB |
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| **[quiet](#quiet) ( )** | Suppress all error logging events from this node. |
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### Chaining Methods
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[Alert](#alert),
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[Barrier](#barrier),
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[Bottom](#bottom),
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[ChangeDetect](#changedetect),
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[Combine](#combine),
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[Count](#count),
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[CumulativeSum](#cumulativesum),
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[Deadman](#deadman),
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[Default](#default),
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[Delete](#delete),
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[Derivative](#derivative),
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[Difference](#difference),
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[Distinct](#distinct),
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[Ec2Autoscale](#ec2autoscale),
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[Elapsed](#elapsed),
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[Eval](#eval),
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[First](#first),
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[Flatten](#flatten),
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[HoltWinters](#holtwinters),
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[HoltWintersWithFit](#holtwinterswithfit),
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[HttpOut](#httpout),
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[HttpPost](#httppost),
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[InfluxDBOut](#influxdbout),
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[Join](#join),
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[K8sAutoscale](#k8sautoscale),
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[KapacitorLoopback](#kapacitorloopback),
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[Last](#last),
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[Log](#log),
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[Max](#max),
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[Mean](#mean),
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[Median](#median),
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[Min](#min),
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[Mode](#mode),
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[MovingAverage](#movingaverage),
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[Percentile](#percentile),
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[Sample](#sample),
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[Shift](#shift),
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[Sideload](#sideload),
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[Spread](#spread),
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[StateCount](#statecount),
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[StateDuration](#stateduration),
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[Stats](#stats),
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[Stddev](#stddev),
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[Sum](#sum),
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[SwarmAutoscale](#swarmautoscale),
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[Top](#top),
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[Union](#union),
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[Where](#where),
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[Window](#window)
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---
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## Properties
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Property methods modify state on the calling node.
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They do not add another node to the pipeline, and always return a reference to the calling node.
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Property methods are marked using the `.` operator.
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### Align
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Align start and stop times for queries with even boundaries of the [QueryNode.Every](/kapacitor/v1.5/nodes/query_node/#every) property.
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Does not apply if using the [QueryNode.Cron](/kapacitor/v1.5/nodes/query_node/#cron) property.
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```js
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query.align()
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### AlignGroup
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Align the group by time intervals with the start time of the query
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```js
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query.alignGroup()
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Cluster
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The name of a configured InfluxDB cluster.
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If empty the default cluster will be used.
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```js
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query.cluster(value string)
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Cron
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Define a schedule using a cron syntax.
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The specific cron implementation is documented here:
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https://github.com/gorhill/cronexpr#implementation
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The Cron property is mutually exclusive with the Every property.
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```js
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query.cron(value string)
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Every
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How often to query InfluxDB.
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The Every property is mutually exclusive with the Cron property.
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```js
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query.every(value time.Duration)
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Fill
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Fill the data.
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Options are:
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- Any numerical value
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- null - exhibits the same behavior as the default
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- previous - reports the value of the previous window
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- none - suppresses timestamps and values where the value is null
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- linear - reports the results of linear interpolation
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```js
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query.fill(value interface{})
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### GroupBy
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Group the data by a set of dimensions.
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Can specify one time dimension.
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This property adds a `GROUP BY` clause to the query
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so all the normal behaviors when quering InfluxDB with a `GROUP BY` apply.
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Use group by time when your period is longer than your group by time interval.
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Example:
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```js
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batch
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|query(...)
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.period(1m)
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.every(1m)
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.groupBy(time(10s), 'tag1', 'tag2'))
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.align()
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```
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A group by time offset is also possible.
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Example:
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```js
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batch
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|query(...)
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.period(1m)
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.every(1m)
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.groupBy(time(10s, -5s), 'tag1', 'tag2'))
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.align()
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.offset(5s)
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```
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It is recommended to use [QueryNode.Align](/kapacitor/v1.5/nodes/query_node/#align) and [QueryNode.Offset](/kapacitor/v1.5/nodes/query_node/#offset) in conjunction with
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group by time dimensions so that the time bounds match up with the group by intervals.
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To automatically align the group by intervals to the start of the query time,
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use [QueryNode.AlignGroup.](/kapacitor/v1.5/nodes/query_node/#aligngroup) This is useful in more complex situations, such as when
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the groupBy time period is longer than the query frequency.
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Example:
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```js
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batch
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|query(...)
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.period(5m)
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.every(30s)
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.groupBy(time(1m), 'tag1', 'tag2')
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.align()
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.alignGroup()
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```
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For the above example, without [QueryNode.AlignGroup,](/kapacitor/v1.5/nodes/query_node/#aligngroup) every other query issued by Kapacitor
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(at :30 past the minute) will align to :00 seconds instead of the desired :30 seconds,
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which would create 6 group by intervals instead of 5, the first and last of which
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would only have 30 seconds of data instead of a full minute.
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If the group by time offset (i.e. time(t, offset)) is used in conjunction with
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[QueryNode.AlignGroup,](/kapacitor/v1.5/nodes/query_node/#aligngroup) the alignment will occur first, and will be offset
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the specified amount after.
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NOTE: Since [QueryNode.Offset](/kapacitor/v1.5/nodes/query_node/#offset) is inherently a negative property the second "offset" argument to the "time" function is negative to match.
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```js
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query.groupBy(d ...interface{})
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### GroupByMeasurement
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If set will include the measurement name in the group ID.
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Along with any other group by dimensions.
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Example:
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```js
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batch
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|query('SELECT sum("value") FROM "telegraf"."autogen"./process_.*/')
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.groupByMeasurement()
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.groupBy('host')
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```
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The above example selects data from several measurements matching `/process_.*/ and
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then each point is grouped by the host tag and measurement name.
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Thus keeping measurements in their own groups.
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```js
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query.groupByMeasurement()
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Offset
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How far back in time to query from the current time
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For example an Offset of 2 hours and an Every of 5m,
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Kapacitor will query InfluxDB every 5 minutes for the window of data 2 hours ago.
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This applies to Cron schedules as well. If the cron specifies to run every Sunday at
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1 AM and the Offset is 1 hour. Then at 1 AM on Sunday the data from 12 AM will be queried.
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```js
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query.offset(value time.Duration)
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Period
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The period or length of time that will be queried from InfluxDB
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```js
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query.period(value time.Duration)
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Quiet
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Suppress all error logging events from this node.
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```js
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query.quiet()
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```
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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## Chaining Methods
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Chaining methods create a new node in the pipeline as a child of the calling node.
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They do not modify the calling node.
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Chaining methods are marked using the `|` operator.
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### Alert
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Create an alert node, which can trigger alerts.
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```js
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query|alert()
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```
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Returns: [AlertNode](/kapacitor/v1.5/nodes/alert_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Barrier
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Create a new Barrier node that emits a BarrierMessage periodically.
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One BarrierMessage will be emitted every period duration.
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```js
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query|barrier()
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```
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Returns: [BarrierNode](/kapacitor/v1.5/nodes/barrier_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Bottom
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Select the bottom `num` points for `field` and sort by any extra tags or fields.
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```js
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query|bottom(num int64, field string, fieldsAndTags ...string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### ChangeDetect
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Create a new node that only emits new points if different from the previous point.
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```js
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query|changeDetect(field string)
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```
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Returns: [ChangeDetectNode](/kapacitor/v1.5/nodes/change_detect_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Combine
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Combine this node with itself. The data is combined on timestamp.
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```js
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query|combine(expressions ...ast.LambdaNode)
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```
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Returns: [CombineNode](/kapacitor/v1.5/nodes/combine_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Count
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Count the number of points.
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```js
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query|count(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### CumulativeSum
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Compute a cumulative sum of each point that is received.
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A point is emitted for every point collected.
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```js
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query|cumulativeSum(field string)
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```
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Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
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<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
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### Deadman
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Helper function for creating an alert on low throughput, a.k.a. deadman's switch.
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- Threshold: trigger alert if throughput drops below threshold in points/interval.
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- Interval: how often to check the throughput.
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- Expressions: optional list of expressions to also evaluate. Useful for time of day alerting.
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Example:
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```js
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var data = batch
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|query()...
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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data
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|deadman(100.0, 10s)
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//Do normal processing of data
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data...
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```
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The above is equivalent to this example:
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```js
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var data = batch
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|query()...
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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data
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|stats(10s)
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.align()
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|derivative('emitted')
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.unit(10s)
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.nonNegative()
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|alert()
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.id('node \'stream0\' in task \'{{ .TaskName }}\'')
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.message('{{ .ID }} is {{ if eq .Level "OK" }}alive{{ else }}dead{{ end }}: {{ index .Fields "emitted" | printf "%0.3f" }} points/10s.')
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.crit(lambda: "emitted" <= 100.0)
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//Do normal processing of data
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data...
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```
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The `id` and `message` alert properties can be configured globally via the 'deadman' configuration section.
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Since the [AlertNode](/kapacitor/v1.5/nodes/alert_node/) is the last piece it can be further modified as usual.
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Example:
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```js
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var data = batch
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|query()...
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
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data
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|deadman(100.0, 10s)
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.slack()
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.channel('#dead_tasks')
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//Do normal processing of data
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data...
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```
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You can specify additional lambda expressions to further constrain when the deadman's switch is triggered.
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Example:
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```js
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var data = batch
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|query()...
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// Trigger critical alert if the throughput drops below 100 points per 10s and checked every 10s.
|
|
// Only trigger the alert if the time of day is between 8am-5pm.
|
|
data
|
|
|deadman(100.0, 10s, lambda: hour("time") >= 8 AND hour("time") <= 17)
|
|
//Do normal processing of data
|
|
data...
|
|
```
|
|
|
|
|
|
|
|
```js
|
|
query|deadman(threshold float64, interval time.Duration, expr ...ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [AlertNode](/kapacitor/v1.5/nodes/alert_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Default
|
|
|
|
Create a node that can set defaults for missing tags or fields.
|
|
|
|
|
|
```js
|
|
query|default()
|
|
```
|
|
|
|
Returns: [DefaultNode](/kapacitor/v1.5/nodes/default_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Delete
|
|
|
|
Create a node that can delete tags or fields.
|
|
|
|
|
|
```js
|
|
query|delete()
|
|
```
|
|
|
|
Returns: [DeleteNode](/kapacitor/v1.5/nodes/delete_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Derivative
|
|
|
|
Create a new node that computes the derivative of adjacent points.
|
|
|
|
|
|
```js
|
|
query|derivative(field string)
|
|
```
|
|
|
|
Returns: [DerivativeNode](/kapacitor/v1.5/nodes/derivative_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Difference
|
|
|
|
Compute the difference between points independent of elapsed time.
|
|
|
|
|
|
```js
|
|
query|difference(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Distinct
|
|
|
|
Produce batch of only the distinct points.
|
|
|
|
|
|
```js
|
|
query|distinct(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Ec2Autoscale
|
|
|
|
Create a node that can trigger autoscale events for a ec2 autoscalegroup.
|
|
|
|
|
|
```js
|
|
query|ec2Autoscale()
|
|
```
|
|
|
|
Returns: [Ec2AutoscaleNode](/kapacitor/v1.5/nodes/ec2_autoscale_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Elapsed
|
|
|
|
Compute the elapsed time between points.
|
|
|
|
|
|
```js
|
|
query|elapsed(field string, unit time.Duration)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Eval
|
|
|
|
Create an eval node that will evaluate the given transformation function to each data point.
|
|
A list of expressions may be provided and will be evaluated in the order they are given.
|
|
The results are available to later expressions.
|
|
|
|
|
|
```js
|
|
query|eval(expressions ...ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [EvalNode](/kapacitor/v1.5/nodes/eval_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### First
|
|
|
|
Select the first point.
|
|
|
|
|
|
```js
|
|
query|first(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Flatten
|
|
|
|
Flatten points with similar times into a single point.
|
|
|
|
|
|
```js
|
|
query|flatten()
|
|
```
|
|
|
|
Returns: [FlattenNode](/kapacitor/v1.5/nodes/flatten_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### HoltWinters
|
|
|
|
Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
|
|
|
|
|
|
```js
|
|
query|holtWinters(field string, h int64, m int64, interval time.Duration)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### HoltWintersWithFit
|
|
|
|
Compute the Holt-Winters (/{{< latest "influxdb" "v1" >}}/query_language/functions/#holt-winters) forecast of a data set.
|
|
This method also outputs all the points used to fit the data in addition to the forecasted data.
|
|
|
|
|
|
```js
|
|
query|holtWintersWithFit(field string, h int64, m int64, interval time.Duration)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### HttpOut
|
|
|
|
Create an HTTP output node that caches the most recent data it has received.
|
|
The cached data is available at the given endpoint.
|
|
The endpoint is the relative path from the API endpoint of the running task.
|
|
For example, if the task endpoint is at `/kapacitor/v1/tasks/<task_id>` and endpoint is
|
|
`top10`, then the data can be requested from `/kapacitor/v1/tasks/<task_id>/top10`.
|
|
|
|
|
|
```js
|
|
query|httpOut(endpoint string)
|
|
```
|
|
|
|
Returns: [HTTPOutNode](/kapacitor/v1.5/nodes/http_out_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### HttpPost
|
|
|
|
Creates an HTTP Post node that POSTS received data to the provided HTTP endpoint.
|
|
HttpPost expects 0 or 1 arguments. If 0 arguments are provided, you must specify an
|
|
endpoint property method.
|
|
|
|
|
|
```js
|
|
query|httpPost(url ...string)
|
|
```
|
|
|
|
Returns: [HTTPPostNode](/kapacitor/v1.5/nodes/http_post_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### InfluxDBOut
|
|
|
|
Create an influxdb output node that will store the incoming data into InfluxDB.
|
|
|
|
|
|
```js
|
|
query|influxDBOut()
|
|
```
|
|
|
|
Returns: [InfluxDBOutNode](/kapacitor/v1.5/nodes/influx_d_b_out_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Join
|
|
|
|
Join this node with other nodes. The data is joined on timestamp.
|
|
|
|
|
|
```js
|
|
query|join(others ...Node)
|
|
```
|
|
|
|
Returns: [JoinNode](/kapacitor/v1.5/nodes/join_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### K8sAutoscale
|
|
|
|
Create a node that can trigger autoscale events for a kubernetes cluster.
|
|
|
|
|
|
```js
|
|
query|k8sAutoscale()
|
|
```
|
|
|
|
Returns: [K8sAutoscaleNode](/kapacitor/v1.5/nodes/k8s_autoscale_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### KapacitorLoopback
|
|
|
|
Create an kapacitor loopback node that will send data back into Kapacitor as a stream.
|
|
|
|
|
|
```js
|
|
query|kapacitorLoopback()
|
|
```
|
|
|
|
Returns: [KapacitorLoopbackNode](/kapacitor/v1.5/nodes/kapacitor_loopback_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Last
|
|
|
|
Select the last point.
|
|
|
|
|
|
```js
|
|
query|last(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Log
|
|
|
|
Create a node that logs all data it receives.
|
|
|
|
|
|
```js
|
|
query|log()
|
|
```
|
|
|
|
Returns: [LogNode](/kapacitor/v1.5/nodes/log_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Max
|
|
|
|
Select the maximum point.
|
|
|
|
|
|
```js
|
|
query|max(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Mean
|
|
|
|
Compute the mean of the data.
|
|
|
|
|
|
```js
|
|
query|mean(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Median
|
|
|
|
Compute the median of the data.
|
|
|
|
> **Note:** This method is not a selector.
|
|
If you want the median point, use `.percentile(field, 50.0)`.
|
|
|
|
|
|
```js
|
|
query|median(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Min
|
|
|
|
Select the minimum point.
|
|
|
|
|
|
```js
|
|
query|min(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Mode
|
|
|
|
Compute the mode of the data.
|
|
|
|
|
|
```js
|
|
query|mode(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### MovingAverage
|
|
|
|
Compute a moving average of the last window points.
|
|
No points are emitted until the window is full.
|
|
|
|
|
|
```js
|
|
query|movingAverage(field string, window int64)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Percentile
|
|
|
|
Select a point at the given percentile. This is a selector function, no interpolation between points is performed.
|
|
|
|
|
|
```js
|
|
query|percentile(field string, percentile float64)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Sample
|
|
|
|
Create a new node that samples the incoming points or batches.
|
|
|
|
One point will be emitted every count or duration specified.
|
|
|
|
|
|
```js
|
|
query|sample(rate interface{})
|
|
```
|
|
|
|
Returns: [SampleNode](/kapacitor/v1.5/nodes/sample_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Shift
|
|
|
|
Create a new node that shifts the incoming points or batches in time.
|
|
|
|
|
|
```js
|
|
query|shift(shift time.Duration)
|
|
```
|
|
|
|
Returns: [ShiftNode](/kapacitor/v1.5/nodes/shift_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Sideload
|
|
|
|
Create a node that can load data from external sources.
|
|
|
|
|
|
```js
|
|
query|sideload()
|
|
```
|
|
|
|
Returns: [SideloadNode](/kapacitor/v1.5/nodes/sideload_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Spread
|
|
|
|
Compute the difference between `min` and `max` points.
|
|
|
|
|
|
```js
|
|
query|spread(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### StateCount
|
|
|
|
Create a node that tracks number of consecutive points in a given state.
|
|
|
|
|
|
```js
|
|
query|stateCount(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [StateCountNode](/kapacitor/v1.5/nodes/state_count_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### StateDuration
|
|
|
|
Create a node that tracks duration in a given state.
|
|
|
|
|
|
```js
|
|
query|stateDuration(expression ast.LambdaNode)
|
|
```
|
|
|
|
Returns: [StateDurationNode](/kapacitor/v1.5/nodes/state_duration_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Stats
|
|
|
|
Create a new stream of data that contains the internal statistics of the node.
|
|
The interval represents how often to emit the statistics based on real time.
|
|
This means the interval time is independent of the times of the data points the source node is receiving.
|
|
|
|
|
|
```js
|
|
query|stats(interval time.Duration)
|
|
```
|
|
|
|
Returns: [StatsNode](/kapacitor/v1.5/nodes/stats_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Stddev
|
|
|
|
Compute the standard deviation.
|
|
|
|
|
|
```js
|
|
query|stddev(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Sum
|
|
|
|
Compute the sum of all values.
|
|
|
|
|
|
```js
|
|
query|sum(field string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### SwarmAutoscale
|
|
|
|
Create a node that can trigger autoscale events for a Docker swarm cluster.
|
|
|
|
|
|
```js
|
|
query|swarmAutoscale()
|
|
```
|
|
|
|
Returns: [SwarmAutoscaleNode](/kapacitor/v1.5/nodes/swarm_autoscale_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Top
|
|
|
|
Select the top `num` points for `field` and sort by any extra tags or fields.
|
|
|
|
|
|
```js
|
|
query|top(num int64, field string, fieldsAndTags ...string)
|
|
```
|
|
|
|
Returns: [InfluxQLNode](/kapacitor/v1.5/nodes/influx_q_l_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Union
|
|
|
|
Perform the union of this node and all other given nodes.
|
|
|
|
|
|
```js
|
|
query|union(node ...Node)
|
|
```
|
|
|
|
Returns: [UnionNode](/kapacitor/v1.5/nodes/union_node/)
|
|
|
|
<a class="top" href="javascript:document.getElementsByClassName('article-heading')[0].scrollIntoView();" title="top"><span class="icon arrow-up"></span></a>
|
|
|
|
### Where
|
|
|
|
Create a new node that filters the data stream by a given expression.
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```js
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query|where(expression ast.LambdaNode)
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```
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Returns: [WhereNode](/kapacitor/v1.5/nodes/where_node/)
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### Window
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Create a new node that windows the stream by time.
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NOTE: Window can only be applied to stream edges.
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```js
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query|window()
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```
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Returns: [WindowNode](/kapacitor/v1.5/nodes/window_node/)
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